Detection of effects of ozone on birch, Betula pendula Roth., by chemometrical evaluation of concentrations of lipid components in leaves

Birch trees were exposed to ozone-free air and air containing 150 and 300 μg O3/m3 in open-top chambers, as well as ambient air. Lipid components, mainly fatty acids, in the leaves were determined by methanolysis, gas chromatography and principal component analysis of the Chromatographic data. A decrease in the absolute amounts and a change in the relative amounts of the components was observed after three months of exposure. These effects occurred before visible damage of the leaves could be observed, and may be used as biomarker for ozone stress on trees.